A bacterial pioneer produces cellulase complexes that persist through community succession

Abstract

Cultivation of microbial consortia provides low-complexity communities that can serve as tractable models to understand community dynamics. Time-resolved metagenomics demonstrated that an aerobic cellulolytic consortium cultivated from compost exhibited community dynamics consistent with the definition of an endogenous heterotrophic succession. The genome of the proposed pioneer population, 'Candidatus Reconcilibacillus cellulovorans', possessed a gene cluster containing multidomain glycoside hydrolases (GHs). Purification of the soluble cellulase activity from a 300litre cultivation of this consortium revealed that ~70% of the activity arose from the 'Ca. Reconcilibacillus cellulovorans' multidomain GHs assembled into cellulase complexes through glycosylation. These remarkably stable complexes have supramolecular structures for enzymatic cellulose hydrolysis that are distinct from cellulosomes. The persistence of these complexes during cultivation indicates that they may be active through multiple cultivations of this consortium and act as public goods that sustain the community. The provision of extracellular GHs as public goods may influence microbial community dynamics in native biomass-deconstructing communities relevant to agriculture, human health and biotechnology.

Xylanolytic Extremozymes Retrieved From Environmental Metagenomes: Characteristics, Genetic Engineering, and Applications

“…Recently, three α-L-arabinofuranosidases (AFaseH4, AFaseE3, and AFaseD3) have been reported from the high-temperature compost metagenome (Matsuzawa et al, 2015;Fortune et al, 2019). On characterization, all three display optimum activity at pH in the acidic range of pH 4.0-5.0 and at 40 • C. However, sequence analysis reveals that AFaseH4and AFaseE3-encoding genes share 100 and 99% identity with the existing sequences, respectively, while the ORF-encoding AFaseD3 shares 77% identity with the AFAse of a Paenibacillus taihuensis ORF (Kolinko et al, 2018). Many other metagenomic arabinofuranosidases have shown activity with β-xylosidases as bifunctional enzymes (Wagschal et al, 2009;Wang et al, 2015;Jordan et al, 2016).…”

Forfeiting the founder effect: turnover defines biofilm community succession

“…Much remains unknown about the roles that colonizing microbes play in influencing the future states of their respective microbiomes. Hence, microbial community succession remains an active area of research (Castle et al 2017, Knelman et al 2018, Kolinko et al 2018. We do know, however, that these processes can be influenced by both deterministic and stochastic factors (Nemergut et al 2013, Vellend 2010, Zhou and Ning 2017.…”

Domain architecture divergence leads to functional divergence in binding and catalytic domains of bacterial and fungal cellobiohydrolases

“…Recently, a cellulase containing a GH6 CBH from Reconcilibacillus cellulovorans (RcCelC) has been reported ( 32 ). Domain composition of this enzyme is GH6-GH5-CBM3, and GH6 CD is similar to the bacterial one.…”